Well, if I'm on the right track here, I usually take the long way: click on 'insert', go down to 'symbol' and finally make sure the 'font' box states 'Andale Mono IPA' (IPA = International Phonetic Alphabet). You'll find almost all your options available right here. For vowels with the different lines above them, change from 'Andale Mono IPA' to 'norml text'.

I'm unaware of another shorter method but I hope you can make sense of it. I use Word 2000 so I hope all my details are helpful even if you're not using the same version.

SIL's fonts were a good option in times fonts were one-byte (256-character-) sized. Now I prefer to stick to an internatinal standard (Unicode) rather than use proprietary codepages (e.g. SIL). The advantage of Unicode fonts is that they are likely to last for a much longer time than any proprietary format. In addition, font designers are likely to create new typefaces in the Unicode format. If you intend to actually print your works, this is a strong argument. For example, you can try Lucida Sans Unicode, which is (I believe) shipped with Windows XP. The thing with this font is that at first sight you do not see the phonetic symbols. But they are there!

Where are the IPA symbols? The Phonetic symbols of Unicode fonts (e.g. of Lucida Sans Unicode) can be found in the "Latin extended", the "Spacing Modifier Letters", and the "Combining diacritical marks" subsets of Unicode fonts. To view them, open the Windows Character Map, choose "Group by: Unicode subset" and choose the appropriate subset.

Pros and Cons of Lucida: Lucida covers most (but not all) IPA characters, although you will see it covers most languages, including all western European languages, Russian, Arabic, and many more.
A drawback for some languages is that some of the diacritical marks extending below the base line are not displayed properly in this font, but, at least, you have your characters in the right (Unicode-standard) place.

A good alternative to Keyman: Keyman is fine, but it is a resident software that will take away some of your system's resources. It is better to use a native Windows Phonetic keyboard. And yes, now you can edit them! Microsoft has (relatively recently) published a keyboard layout editor called Microsoft Keyboard Layout Creator (MSKLC.exe).
Download it from http://www.microsoft.com/

A final tip: Finally, I would like to suggest VTrain (Vocabulary Trainer), a flashcard-based program that includes several on-screen keyboards for Phonetic (IPA) symbols. These keyboards allow you to enter the phonetic characters by simple mouse clicks.
You will find it at http://www.vtrain.net/home.htm